Rotary piston air pump



July 21, 1953 A. BRAM ROTARY PISTON AIR PUMP Filed Dec. 8, 1948 WWW T5. N N R N T 4% m A Y 4MB I Patented July 21 1953 v UNITED STATES ROTARY PISTON gin crimp Alfred Bram, Schlicren, Switzerland, ass ignor to 'MicafilA.-GL;Zurich-Alstetten, Switzerland I 5 Ap ica em r' 8, 1948, r al N 6 970 In Switzerland Decemberfi, 1947 The invention refers to arot'ary piston air pump for use with gases and vapors, the-pump being immersed in oil contained in a container and provided with at least one radially movable blade and an oil .seal, as well as with an outlet having an exhaust valve arranged below the oil I level in'the containerand with a; second outlet means terminating in the. atmosphere above the oillevel. f I.

Pumps of this type are. often used for pumping damp vapors. Since the sealing oil inside the pump comes into close contact with the vapors, the oil becomes saturated and an emulsion is formed after-a time. Generally, not all of the pump and easing parts have the same temperature, and heavy over-saturated oil collects and becomes stationary particularly in the relatively cool lower part of the container, so that condensate forms there. The condensate displaces the oil and disturbs the operation of the pump.

'The object of the present invention is to prevent the super-cooling of stagnating oil portions and to relieve the oil of the damp vapors which are enclosed in it. According to the invention this is achieved by providing the pump with a device for introducing contaminatedsealing oil from the lowest point of the container into the pump chamber. Flow of oil into the pump is assured by the low pressure in the chamber until it is connected with the pump outlet and the relatively high atmospheric pressure inthe container. The condensate which is sucked into the tion pipei and is termed the suction chamber.

In this chamber 11 there is suction pressure, that is' a pressure'that is below that of the'atmosphere. In accordance with the "invention for this position of the piston, that is with each sucticn stroke, thesuction chamber 10 is connected with the lowest "point of the sealing-Oil cone tainera'f For this p-urpo se'it is an advantage to provide the container a with an inclined bottom. The connection betweenthe suction chamber and the lowest point'o'f the "container a is achieved by means of a pipe '0' which is provided with a stop valve 1 for regulating the flow of oil.

The pipe q can either be arranged outside of the container a and connected to the lowest point of the latter as shown in Fig. l, or the pipe I q together with the valve r can be located inside I chamber p, the vapors contained in the oil are released therefrom. Both, oi1 and vapor, are exchamber of the pump together with theseal'ing oil evaporates due to the lower pressure in the pump and, as the piston continues to rotate, the vapors and the oil are expelled through the exhaust outlet of the pump into the container. The vapors exhaust'through a vent in the top of the container and the oil collects in the-container.

Two constructional examples of the invention are illustrated in the accompanying drawing.

Fig. 1 shows, diagrammatically, a rotary piston air pumo according to the invention in section.

Fig. 2 illustrates, diagrammatically, a modified pump, according to the invention. also in section.

.Fig. 3 is a'longitudinal large scale sectional view of a pump outlet valve.

In both examples the pump is built'into a con- I tainer a which is closed by a cover I), the container being filled with sealing oil up to the mark 0. The piston or rotor f rotates about its axis inside the pump casing e in the direction indicated by the arrow. The two blades 9 together with the piston f and the wall of the casing e form a space p which is shut oiT from the sucthe oil level 0, and the vapor escapes through outlet icy For producinga higher vacuum outlet Z is provided with a valve, not shown, which is closed so that the sealing oil is passed with the air through the additional outlet m which is disposed between the inlet 2' and the outlet [substanl. A rotary vacuum pump comprising, in combination, a containercont-ainingsealing oil and having an outlet to the atmosphere, a, pump casing. having a chamberdisposed in said container and being submersed in the sealing oil, inlet dividing the space in'said chamber into a suction anda delivery portion, and a sealing oil supply conduit extending from substantially the lowest point of said container into the delivery portion of said pumpchamber.

2. A rotary vacuum pump as defined in claim 1, comprising a regulating valve in said conduit.

3. A rotary vacuum pump as defined in claim 1, said sealing oil conduit being disposed within said container.

4. A rotary vacuum pump as defined in claim 1, said sealing oil conduit being disposed substantially outside of said container. combination, a container partly filled with oil 5. A rotary vacuum pump, comprising, in combination, a container partly filled with oil and having an outlet to the atmosphere, a substantially horizontal cylindrical pump casing having a chamber disposed in said container, a. rotor eccentrically mounted in said chamber and being tangent to the upper portion of the inside of said casing, pump blades radially movably fitted in said rotor along a diameter thereof, inlet means for the medium to be pumped connected with the upper portion of said chamber at one side of thel'part of the chamber where said rotor is tangent to 'said casing, outlet means vfor the.

pumped fluid connected with said chamber at the other side of the part of the chamber where said.

4 sealing. oil into said chamber and for being at all times non-communicating with said inlet means, and an additional outlet means connected with said casing at the upper portion of the pump chamber between said inlet means and said first outlet means and substantially at the place where said rotor is tangent to said casing.

ALFRED BRAM.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,142,544 Vernon et a1. June 8, 1915 1,346,165 Berrenberg July 13, 1920 1,352,750 Jackson Sept. 14, 1920 1,558,788 Campbell Oct. 27, 1925 1,615,824 Bell Feb. 1, 1927 1,732,039 Cuthbert Oct. 15, 1929 1 ,781,095 Blood Nov. 11, 1930 1,967,033 Lipman July 17, 1934 1,970,033 7 Dennedy Aug. 14, 1934 2,138,664 Money Nov. 29, 1938 FOREIGN PATENTS Number Country Date 6,938 Great Britain of 1910 94,373 Sweden' Oct. 27, 1938 116,014 Australia Oct. 13, 1942 223,375 Switzerland Dec. 1, 1942 480,993 Great Britain Mar. 3, 1938 742,876 France Jan. 4, 1933 

